This application is aimed at establishing a national resource on medical ultrasonic transducer technology at the Pennsylvania State University with an emphasis on the development of very high frequency (30 to 200 MHz) transducer/array technology. Ultrasonic imaging is one of the most important imaging modalities today because it possesses several advantages over other imaging modalities like x-ray radiography, x-ray computed tomography, magnetic resonance imaging and nuclear imaging in that it is noninvasive, capable of real-time tomographical imaging, relatively inexpensive and portable. The cost-effectiveness of the modality makes it the method of choice for future development since curtailing the rising health care cost is a national agenda. Current ultrasonic scanners operated in the frequency range between 2 to 30 MHz have a spatial resolution on the order of 0.5 to 3 mm which is well below the theoretical limit. Transducer performance is one of the primary limiting factors and much improvement can be made. The fundamental reason is that ultrasonic transducer technology involves multiple disciplines requiring knowledge in material sciences, acoustics, electrical engineering, and mechanical engineering in addition to anatomy and physiology. Presently there is no academic facility in the country that is capable of offering assistance in the design and fabrication of array transducers to academic institutional and small companies that cannot afford the cost in building such a facility. The applications of ultrasonic imaging in the frequency range beyond 30 MHz, particularly in the very high frequency (VHF) range, in ophthalmology and dermatology and in vascular imaging, are currently under intensive investigation but are hampered by the lack of imaging arrays beyond 15 MHz. Array transducer technology in this frequency range is an almost unexplored territory. The infrastructure for such a resource already exists at Penn State because of the receipt of a Whitaker Foundation Special Opportunity award which allowed the establishment of the Whitaker Center for Medical Ultrasonic Transducer Engineering and the purchase of major pieces of equipment necessary for the design and fabrication of ultrasonic transducers and arrays. The facilities and expertise of the Center coupled with those of the Materials Research Laboratory and the Applied Research Laboratory which have long outstanding records of achievements for research in ferroelectric materials and sonar array engineering make Penn State a unique institution exceptionally qualified for the institution of a national resource on medical ultrasonic transducer technology.